This invention pertains to a device making it possible to grasp an implant, implant the implant and manipulate the implant, of the type comprising prehension means intended to cooperate with receiving means. The field of application is that of spinal osteosynthesis devices.
Spinal osteosynthesis devices are traditionally arranged on the vertebral column by means of implants that are fixed, for example, in the pedicles. Thus, these implants can be, for example, pedicle screws. Grasping these implants by specific instruments is required for their installation on the spine.
It is not always easy to grasp the implant with the specific instrument because of the position of the implants (sometimes almost horizontal), because of the mobility of the implants (principally for hooks) and because of the constraints of congestion in the wound (surrounding tissues, depth of the wound, bony parts, etc.). In addition, installation of a spinal osteosynthesis device requires implementation of correction operations on the implants. During these correction operations, it is also necessary to hold these implants firmly either for introducing the connecting element (rod), or for installation or for maintaining the implants in their optimum positions.
In order to do this, one uses surgical instruments comprising particular prehension devices capable of cooperating with receiving means provided, for example, on said implant. Three types of implant prehension systems are presently available:
First type: A cylinder is provided on the instrument and this cylinder can cooperate with a hole provided on the implant. The prehension device furthermore has a stop which, when it comes into contact with a slot provided at the periphery of the hole or on the top of the implant, makes possible holding and rotational locking. This solution is acceptable, rather easy to install, but requires a large surface area on the implant for the prehension holes.
Second type: The invention has two pins which can cooperate with two holes provided on the implant. This attachment system requires perfect alignment of the implant and the instrument, and makes in-situ prehension very difficult.
Third type: An oblong hole is provided on the implant and the instrument has a projection of corresponding shape. This system also requires perfect alignment and makes anchoring very difficult.
This invention relates to a prehension device for grasping an implant, implanting the implant and manipulating the implant, including prehension means cooperative with receiving means, wherein prehension means has in longitudinal section an arc-shaped form, the peripheral edges of which are provided with at lest one peripheral chamfer and the arc-shaped form has at one end at least one cylinder.